Renewable feedstocks, such as fatty acids or fatty esters derived from natural oils, have opened new possibilities for the development of industrially useful organic compounds. For example, renewable feedstocks can be used to prepare compounds that are not readily obtainable from conventional petroleum feedstocks. In another example, renewable feedstocks can be used to prepare known compounds more efficiently, without requiring undesirable reagents or solvents, and/or with decreased amounts of waste or side products.
Metathesis reactions can be used to convert natural oils and their fatty acid or fatty ester derivatives into useful renewable feedstocks. When compounds containing a carbon-carbon double bond undergo metathesis reactions in the presence of a metathesis catalyst, some or all of the original carbon-carbon double bonds are broken, and new carbon-carbon double bonds are formed. The products of such metathesis reactions include carbon-carbon double bonds in different locations, which can provide unsaturated organic compounds having useful chemical structures. Examples of useful unsaturated organic compounds that can be produced by metathesis reactions with natural oils or their derivatives include olefin ester compounds, e.g., terminal olefin esters such as “α-ester-alk-ω-ene molecules”, for instance 9-decenoic acid methyl ester (9-DAME) and internal olefin esters, such as “α-ester-alk-ψ-ene molecules”, for instance 9-dodecenoic acid methyl ester (9-DDAME).
Dibasic acids, such as dicarboxylic acids or their esters, are used to make a variety of different materials, including, but not limited to, polyamides, polyesters, and polyanhydrides. While some dicarboxylic acids can be readily synthesized from conventional petroleum-based feedstocks, others cannot. Suberic acid is one non-limiting example of an industrially useful organic compound that is difficult to prepare from conventional petroleum feedstocks. Suberic acid is one of a class of aliphatic, linear dicarboxylic acids having the chemical formula HOOC—(CH2)n—COOH, which are useful organic compounds having a variety of commercial applications. Some members of this class of dicarboxylic acids, such as adipic acid (n=4), azelaic acid (n=7), sebacic acid (n=8), and dodecanedioic acid (n=10), are produced commercially on relatively large scales. These dicarboxylic acids may be described as C6, C9, C10 and C12 dicarboxylic acids, respectively, where the subscript refers to the number of carbon atoms in the linear aliphatic chain, including the carbon atoms of the carboxylic acid groups. Suberic acid (n=6; C8 dicarboxylic acid), however, is not readily produced on a large scale.
The lack of commercially available suberic acid can represent a gap in the toolbox of synthetic chemistry. The values of properties such as melting point, refractive index, and decarboxylation temperature alternate as the number of carbon atoms in the aliphatic, linear dicarboxylic acids changes between even numbers and odd numbers in the series of C2 to C12. For example, in species below C12 the odd numbered dicarboxylic acids have lower melting points and higher solubilities in water than do the even numbered dicarboxylic acids before and after them in the series. These differences in properties of the dicarboxylic acids can result in macroscopic differences in the properties of polymers formed from monomers that include the acids. While adipic (C6) and sebacic (C10) acids are commonly used as monomers for polyamides, polyesters and polyurethanes, suberic acid (C8) is not commonly used due to its relative lack of availability. Thus, polymers formed using suberic acid, which would have properties between those of polymers formed using adipic acid or sebacic acid, are not readily available.
It would be desirable to provide methods of making useful organic compounds, such as suberic acid, from renewable feedstocks. In one example, it would be desirable to provide methods of making other useful organic compounds from 9-decenoic acid methyl ester. In another example, it would be desirable to provide methods of making useful organic compounds such as suberic acid from renewable feedstocks, such as 9-decenoic acid methyl ester. Preferably the methods of making useful organic compounds from renewable feedstocks can be performed using smaller amounts of solvents and/or reagents relative to conventional processes, and/or can produce smaller amounts of undesirable side products.